In a certain code language, 'TREE' is written as 'WWHJ', and 'LEAF' is written as 'OJDK'. How will 'BARK' be written in that language?

The positional values of the letters in alphabetical order are used to determine the logic:
For 'TREE' → 'WWHJ':

T(20)+3=W(23)

R(18)+5=W(23)

E(5)+3=H(8)

E(5)+5=J(10)
The pattern is alternating additions of +3 and +5.

Let's check 'LEAF' → 'OJDK':

L(12)+3=O(15)

A(1)+4→ Let's re-verify the vowel/consonant pattern.
Alternatively, look at the positions:

L(12)+3=O(15)

E(5)+5=J(10)

A(1)+3=D(4)

F(6)+5=K(11)
So the operation is consistently +3,+5,+3,+5 across the positions.

Applying the same logic to 'BARK':

B(2)+3=E(5)

A(1)+5=F(6)

R(18)+3=U(21)

K(11)+5=P(16)

Thus, 'BARK' is coded as 'EFUP'.